The present invention generally relates to a manufacturing planning system. More particularly, the invention is concerned with a manufacturing planning system which incorporates functions for generation or creation of production schedules, adjustments or alterations thereof and user interfacing.
As a manufacturing planning system of the type mentioned above, there is hitherto known a system in which fixed production process sequences, a lead time (i.e. the number of days estimated as demanded for completion of a product to be manufactured) and the number of shop workdays determined on the side of a manufacturer are inputted for automatically planning an optical production schedule including optimal start and completion dates of the individual processes which are determined by counting back the number of days from a designated date at which manufacturing of the product is to be completed (hereinafter also referred to as the product completion date), as is disclosed, for example, in JP-A-62-26509.
In the known system mentioned above, the fixed process sequences and the lead time determined on the side of the manufacturer are used for creating a planned process schedule which is then displayed in comparison with a schedule which will be accompanied with the latest start date. However, this known planning system incorporates no functions for alteration and adjustment of the production schedule once established. More specifically, when there arises a fear that the schedule can not be achieved on or before the day designated for completion of the product, it becomes necessary to alter or adjust the production schedule by taking measures for shortening the period of production such as increasing the production capability or capacity by resorting to overtime work and/or operating an alternative shop. However, this sort of adjusting function is not incorporated in the known system mentioned above. It is further noted that when the production capability or capacity is changed for adjustment of the production schedule, the lead times of the individual processes will undergo corresponding changes. Similarly, alterations of the shops and the production start/completion dates will bring about changes in the lead times of the individual manufacturing processes. Consequently, in order to effectuate the alteration and adjustment of the production schedule, it is naturally required to take into consideration the change in the lead time as involved.
In the known manufacturing planning system mentioned above, the lead time itself is determined on the user side. However, in a manufacturing planning system for the manufacturing of ordered products, it is extremely difficult to determine on the user side the lead time by taking into consideration the types of the product, the appointed date of delivery and the production process or shop states, although it depends on types of constituents or parts of the ordered product of concern and multiformity of the manufacturing processes.